What would you do?

Okay this may sound weird funny or whatever BUT is a serious question trust me :P So..tomorrow Iam going for vacations in an Island with 2 other friends of mine and we will stay in my friends home. The thing is we will live in the same house with her parents and her whole family. The thing is when Iam that is very difficult for me to use the bathroom (you know what I mean) when there is someone else in the house (even my parents sometimes) (and even if they go I always worry they will come back) .. so how I can make myself feel relaxed and don't worry too much about that thing? I need to help myself use the bathroom for my needs :p even if there is someone else in the house but is VERY hard for me.. I'll stay for 5 days so I will have to. what would you do in my position?